A program is proposed which will validate new and existing urinary assays for reproductive function in men and women and will extend our previous work in this area. The addition of these methods to those that presently exist will provide multiple biomarkers for ovarian function, pituitary gonadotropin secretion, early fetal loss (EFL) and spermatogenesis. Epidemiologists and biostatistitions will work with clinical and basic scientists to develop innovative data collection and analysis strategies in order to utilize multiple biomarkers and identify reproductive events which cannot be detected with existing methods. Specifically, three practical enzyme immunoassays will be produced. First, an assay for LH and its alpha subunit (LH/LH alpha) will be optimized and validated for evaluating pituitary function for use in identifying the day of ovulation in normal menstrual cycles and differentiating ovarian versus pituitary defects in abnormal menstrual cycles. Second, a relaxin assay will be developed for application to urine samples and will be used to detect defects in luteal function and distinguish between trophoblastic and ovarian causes of EFL. Third, an assay for androsterone-3-glucuronide (A-3-G) will be used to test the hypothesis that a combined measure of urinary progesterone metabolites will provide a more accurate assessment of luteal function than pregnanediol-3-glucuronide (PdG) alone. In addition to the validation of these methods for use with women, the LH/LH alpha will be applied to male urine samples to establish a method for the surveillance of male reproductive function using only self-collected urine samples. These advances will enable epidemiologists to extend their observations beyond the identification of adverse effects and allow them to focus on the target and mechanism of toxic exposure at the organ system level.